In general, swimmers generally possess hypermobile shoulders.
And by hypermobile, I mean greater than necessary ranges of motion and subsequently, often lacking synchrony of instantaneous neuromuscular firing in the scapulothoracic and/or glenohumeral joint regions.
As a result, we know that since the body will always find the "easy way out", compensatory patterns and presentations commonly occur.
And often, one of these presentations is reactive posterior cuff hypertonicity as a protective measure against further injury and/or pain. Whether it leads to bicipital tendon pathology, bursa irritation or other is besides the point. The main point, in my opinion, is why are some individuals still so enamoured by the sleeper stretch? I mean, for any given shoulder injury, presentation or diagnosis, out comes the sleeper stretch.
In my mind, there's a difference between stiffness and hypertonicity. And sure, the glenohumeral joint "needs" adequate mobility. But perhaps more important, the GH joint needs dynamic, instantaneous neuromuscular control. And when we go to town with the sleeper stretch, we get sloppy. ESPECIALLY in swimmers!
Because really, should we be treating the compensation or the cause?
In a similar light, swimming mechanics incorporate both open and closed chain movements. Or in a Prague sense, alternating both support and stepping/grasping functions (read this article if you're unfamiliar with what I'm talking about). Now it's quite common for me to see corrective exercise prescription for the latter - YTWL's, theraband internal/external rotations, etc - but what I rarely see is the former.
Coincidentally, here's a timely clip from Gray about motor control, stability and prime mover training:
Because from the catch to (at least) the end of the pull falls under the "support function" category, in my opinion of course. And since this is the case, closed chain exercises should be the primary focus. Particularly if this is where mechanics are most faulty during skill execution.
So my recommendation to other clinicians is this...
It's okay to think critically and ask yourself why. Why you are seeing what you are seeing. And why you are doing what you are doing.